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Is the Microsoft Online Services Sign-In Assistant necessary

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Hi, we are currently migrating users from our on premise exchange 2007 system to office 365. The users currently have Outlook 2007 installed.  The email addresses will be the same after they have been migrated to 365, but with a different set of credentials...we are not using ADFS.


What benefit does installing Microsoft Online Services Sign-In Assistant  on every PC give me over getting users to login to the portal, change their passwords, reopen outlook (which was pointing at our on premise server) and then enter their login details when prompted via autodiscover.


What would happen if I didnt use the Sign In Assistant?




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  • THe Office 365 SignIn Assistant tool is more of an update the the computer Operating System than a GUI interface.  I strongly recommend that it is installed on the computers.  It assists with the login process for clients to authenticate to Office 365.

  • Great the process is

    a) Users change password using OWA

    b) Install SignIn Assistant

    c) Open Outlook which should autodiscover the new details

  • Hi Mac_365,

    Thanks for Sean’s valuable effort.

    It’s correct that we need to install the Sign-In Assistant in both SSO (Single Sign-on) and un-SSO environment. For more information, please refer to Description of Microsoft Online Services Sign-In Assistant (MOS SIA)

    Regarding to the process you listed above, Step a and Step b is correct. However, at Step c, though the AutoDiscover may connect your current Outlook profile to Exchange Online account, it’s recommend to create a new Outlook profile for use.

    Here are the recommended steps:
    a) Users change password using OWA.
    b) Install SignIn Assistant.
    c) Create a new Outlook profile, configure Exchange Online account with the new profile.

    If you have any additional questions, please feel free to post them in the forum.

    Best Regards,
    Evan Zhang

  • Hi Mac_365,

    How are things going? Did my above information help you or do you need any further assistance?


    Evan Zhang

  • Hi

    Thank you for the information.  We are currently doing a suspended migration of our mailboxes and will be finishing off each account and switching Outlook profiles next week.

    Just to confirm the process for a user

    a) Finish the suspended migration for a user

    b) Get user to sign into OWA and change password

    c) Install sign in assistant on users PC

    d) Open Outlook and create a new profile etc.

  • Hi Mac_365,

    The process is correct.

    If you encounter any other issues when using Office 365 in the future, please feel free to post the questions in the forum.

    Best Regards,

    Evan Zhang

  • Hi

    We have now more or less finished the migration.  The only problem we have is that our AD accounts for several users are being locked with the following message

    675,AUDIT FAILURE,Security,Thu May 31 10:20:40 2012,NT AUTHORITY\SYSTEM,Pre-authentication failed:     User Name: <User>     User ID:  <User ID>     Service Name: krbtgt/<Domain>     Pre-Authentication Type: 0x0     Failure Code: 0x19     Client Address: IP Address     Certificate Issuer Name: %7     Certificate Serial Number: %8     Certificate Thumbprint: %9

    This appears 4 to 5 times and then locks.  Our domain is Windows Server 2003, and the accounts locking are on XP machines.

  • I have seen your another post  If you haven't deployed SSO, this couldn't be an Office 365 problem but local AD problem.

  • The Description of Microsoft Online Services Sign-In Assistant (MOS SIA) was moved to